These dietiest were worthsiped during the early 6th. But during the middle ages, the slavic countries were taken over by the christians. many of their records were kept orally or early writings were done by christian missionsaries with the intent of making the practices look undesirable.
The “Old-believers” in Slovenia gather each year to celebrate the holidays that are related to the four seasons and the equinox period called Jarilo, Mara, Kresnik and Bozhic Svarozhic, as well as to commemorate Perun’s and Veles’ Day.The Old-believers are also organiziers of international meetings and conferences in the Struga castle in Otochec that are named “Veche Rodne Vere” (or Gathering of Native faith). In 2010, the participators of the conference published the journal “Triglav” which was dedicated to the Slovenian native faith.
please note most of this information comes from other sources - I have not yet started working with a diety where I can confidently give my own advice, I will update when I can with my own two cents. Credit given to online sources where possible.
Perun God of thunder and lightning. Ruler of mortal world and heavens - pre-christian slavics believed in the concept of the sacred world tree where the trunk is the land of hte mortals, the roots the underworld and the branches are the heavens. Often in conflict with Veles, overseer of right and order
Christian Alias: St. Elias
Visuals: Male, bearded or with mustache, carries an ax, sometimes an ox or an eagle, riding a chariot pulled by goats
Festival: Feast of Perun (successful harvest), Perun's Day or Perunica (June 21st aka St. Iliya's Day), winter solstice,thursdays, first thunderstorm of the year, July
Associations: Oak trees (A sacred tree representing strength and endurance.), axes ( A tool of both creation and destruction, symbolizing his duality), lightening ( The manifestation of his wrath and power over the elements.)the number 9, eagles (his divine messenger), hilltops, stone idols, truth
Helps with: Oaths (story of Prince Oleg and Prince Igor who made a treaties at the shrine of Perun), sacred spaces, personal struggles, spiritual journeys
When Perun strikes Veles, rain falls—symbolizing victory and fertility for the land.
The rivalry between Perun and Veles is a clasic cosmic dualism of chaos vs order. Perun's victory is the spring and summer whereas Veles's is the winter
Symbols: these represent the thunderbolts or sunwheels
Relative practices: Many people wear ax jewelry or carry an ax (thunderstones) as a sign of protection, called upon every time to make the space sacred with a sacrificial offering, interceed for good weather, successful harvest and protection from evil, offer up acts of bravery, lighting bonfires, weather divisions
Makosh Aka the great weaver, spinner of destiny. Calm personality, merciful, values hard work and perseverence. Often placed near wells, associated with fertility and "women's work". Magical embroidery is associated with her. Messengers are spiders, ants and bees since they are hardworking. Celebrated on Fridays and First Friday of November. Wife of Perun.
Lada mother of perun, goddess of love joy and fertility
KresnikGod of sun, fire and storm, Christian Alias St. John or St. George
Veles God of wisdom, cattle/animals, secrets, and the three afterlife realms. Lives on his own traveling worlds and teaching. Feb 11th is his day.
Morana Goddess of winter, death, and rebirth. Often associated with the "drowning" or burning ritual to bring in the new spring. Child of perun
JarvloChild of Perun, god of spring and agriculture
DziewannaChild of Perun, goddess of wilderness and hunting
Sources: Alter Gods includes the creation story and Perun's ordeals in saving his sisters. Prepovendana Zgodovina (SLO ONLY) The Archaeologist Mythical Encyclopedia Meet the Slavs Mythology Worldwide